code: def num_special_tokens_to_add(self):
      if not hasattr(self, "_num_specials"):
          self._num_specials = (
              self.tokenizer.num_special_tokens_to_add()
          )
      return self._num_specials
  
file_path: OpenPrompt/openprompt/plms/mlm.py
imports: from transformers.models.auto.tokenization_auto import tokenizer_class_from_name
  from openprompt.plms.utils import TokenizerWrapper
  from typing import List, Dict
  from collections import defaultdict
label_desc: Use image node_id 3 for calling the MLMTokenizerWrapper obj's underlying member method code with example usage: obj.num_special_tokens_to_add() and returns: self